package com.tos.graphics;

import com.tos.graphics.LightnessPickerView.OnLightnessChangedListener;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.ColorMatrix;
import android.graphics.Paint;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.SweepGradient;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class HuePickerView extends View {
    private Paint mCirclePaint;
    private Paint mCenterPaint;
    private int[] mColors;
    private OnHueSelectedListener mSelectedListener;
    private OnHueChangedListener mChangedListener;
   
    public interface OnHueChangedListener {
        void hueChanged(int color);
    }

    public interface OnHueSelectedListener {
        void hueSelected(int color);
    }

    HuePickerView(Context context, OnHueChangedListener l, int color) {
        super(context);

        mChangedListener = l;
        init();
        mCenterPaint.setColor(color);
    }

    public HuePickerView(Context context, AttributeSet attrs) {
        super(context, attrs);
       
        init();
    }

    private void init() {
        mColors = new int[] {
                0xFFFF0000, 0xFFFF00FF, 0xFF0000FF, 0xFF00FFFF, 0xFF00FF00,
                0xFFFFFF00, 0xFFFF0000
        };
        Shader s = new SweepGradient(0, 0, mColors, null);
       
        mCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mCirclePaint.setShader(s);
        mCirclePaint.setStyle(Paint.Style.STROKE);
        mCirclePaint.setStrokeWidth(32);
       
        mCenterPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mCenterPaint.setStrokeWidth(5);
    }
   
    public void setOnHueChangedListener(OnHueChangedListener l) {
        mChangedListener = l;
    }

    public void setOnHueSelectedListener(OnHueSelectedListener l) {
        mSelectedListener = l;
    }

    public void setColor(int color) {
        mCenterPaint.setColor(color);
    }
   
    private boolean mTrackingCenter;
    private boolean mHighlightCenter;

    @Override
    protected void onDraw(Canvas canvas) {
        float r = CENTER_X - mCirclePaint.getStrokeWidth()*0.5f;
       
        canvas.translate(CENTER_X, CENTER_X);
        canvas.drawOval(new RectF(-r, -r, r, r), mCirclePaint);            
        canvas.drawCircle(0, 0, CENTER_RADIUS, mCenterPaint);
       
        if (mTrackingCenter) {
            int c = mCenterPaint.getColor();
            mCenterPaint.setStyle(Paint.Style.STROKE);
           
            if (mHighlightCenter) {
                mCenterPaint.setAlpha(0xFF);
            } else {
                mCenterPaint.setAlpha(0x80);
            }
            canvas.drawCircle(0, 0,
                              CENTER_RADIUS + mCenterPaint.getStrokeWidth(),
                              mCenterPaint);
           
            mCenterPaint.setStyle(Paint.Style.FILL);
            mCenterPaint.setColor(c);
        }
    }
   
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        setMeasuredDimension(CENTER_X*2, CENTER_Y*2);
    }
   
    private static final int CENTER_X = 100;
    private static final int CENTER_Y = 100;
    private static final int CENTER_RADIUS = 32;

    private int floatToByte(float x) {
        int n = java.lang.Math.round(x);
        return n;
    }
    private int pinToByte(int n) {
        if (n < 0) {
            n = 0;
        } else if (n > 255) {
            n = 255;
        }
        return n;
    }
   
    private int ave(int s, int d, float p) {
        return s + java.lang.Math.round(p * (d - s));
    }
   
    private int interpColor(int colors[], float unit) {
        if (unit <= 0) {
            return colors[0];
        }
        if (unit >= 1) {
            return colors[colors.length - 1];
        }
       
        float p = unit * (colors.length - 1);
        int i = (int)p;
        p -= i;

        // now p is just the fractional part [0...1) and i is the index
        int c0 = colors[i];
        int c1 = colors[i+1];
        int a = ave(Color.alpha(c0), Color.alpha(c1), p);
        int r = ave(Color.red(c0), Color.red(c1), p);
        int g = ave(Color.green(c0), Color.green(c1), p);
        int b = ave(Color.blue(c0), Color.blue(c1), p);
       
        return Color.argb(a, r, g, b);
    }
   
    private int rotateColor(int color, float rad) {
        float deg = rad * 180 / 3.1415927f;
        int r = Color.red(color);
        int g = Color.green(color);
        int b = Color.blue(color);
       
        ColorMatrix cm = new ColorMatrix();
        ColorMatrix tmp = new ColorMatrix();

        cm.setRGB2YUV();
        tmp.setRotate(0, deg);
        cm.postConcat(tmp);
        tmp.setYUV2RGB();
        cm.postConcat(tmp);
       
        final float[] a = cm.getArray();

        int ir = floatToByte(a[0] * r +  a[1] * g +  a[2] * b);
        int ig = floatToByte(a[5] * r +  a[6] * g +  a[7] * b);
        int ib = floatToByte(a[10] * r + a[11] * g + a[12] * b);
       
        return Color.argb(Color.alpha(color), pinToByte(ir),
                          pinToByte(ig), pinToByte(ib));
    }
   
    private static final float PI = 3.1415926f;

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        float x = event.getX() - CENTER_X;
        float y = event.getY() - CENTER_Y;
        boolean inCenter = java.lang.Math.sqrt(x*x + y*y) <= CENTER_RADIUS;
       
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                mTrackingCenter = inCenter;
                if (inCenter) {
                    mHighlightCenter = true;
                    invalidate();
                    break;
                }
            case MotionEvent.ACTION_MOVE:
                if (mTrackingCenter) {
                    if (mHighlightCenter != inCenter) {
                        mHighlightCenter = inCenter;
                        invalidate();
                    }
                } else {
                    float angle = (float)java.lang.Math.atan2(y, x);
                    // need to turn angle [-PI ... PI] into unit [0....1]
                    float unit = angle/(2*PI);
                    if (unit < 0) {
                        unit += 1;
                    }
                    int color = interpColor(mColors, unit);
                    mCenterPaint.setColor(color);
                    mChangedListener.hueChanged(color);
                    invalidate();
                }
                break;
            case MotionEvent.ACTION_UP:
                if (mTrackingCenter) {
                    if (inCenter) {
                        mSelectedListener.hueSelected(mCenterPaint.getColor());
                    }
                    mTrackingCenter = false;    // so we draw w/o halo
                    invalidate();
                }
                break;
        }
        return true;
    }    
}

